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shielding or feedback/buzzing issue?


lucasd2002

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Hey everybody-

Have had my first HT system up and running now for almost a month.

I have noticed a disturbing problem though. I am getting an intermittent

buzzing/static sound through all speakers. I started with the RF-15s and

recently added the RC-25 (the problem was present before and after the addition

of the center channel). The sound cuts in during tv shows and remains for

anywhere from 30 sec to 10 min. It's the audio version of a snow-storm on

the screen (the actual sound is very faint in the background but cranking the

vol would be way too much static). It is independent of the surr sound

mode on the receiver, volume, tv channel. Turning the power off and back

on does not help. My wife says she has had the problem while watching a

dvd also, but I have only seen it with our dish network box providing the

signal.

We just moved so the setup is only temp with the receiver literally next to the

TV (32" Toshiba) where they are almost touching and dvd and cable box are stacked on the receiver. Is it a shielding

problem?

Receiver is a HK AVR 340 brand new.

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Hi LucasD, I hope you are happy with the center channel I sold you! Huuumm.....what kind of cables are you running? It could be interference with the cables themselves if they are the ones that came with the receiver (assuming they do), but that is a guess. Also, have you tried positioning the receiver a little further away from the TV? Maybe that is the problem. Crosstalk between the receiver and the television is possible I think. Anyone else able to help?

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Make sure your 110 AC voltage cords are not proximity to the RCA cables, the connecting points are on different sides of the units for a reason.

Once that's done try checking if you have a Quarts lamp with a dimmer on th same circuit as the Receiver/amp/preamp. I had this problem and if you turn the lamp off or on to its brightest setting the buzzing goes away.

simple fix. throw the damn light away if that's it.

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There are no halogen lights in the room.

It sounds like a typical feedback with noise in the signal. I guess a cross between the bee and snake. It does not occur 100% of the time but when it does happen, it continues for anywhere from 30 sec to 10 min.

**Update: I moved the receiver away from the tv, dvd, and sat box and have not heard the sound in 2 days. Hopefully, it was noise from 1 or all of the above and the problem is solved. Anybody else seen this issue?

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well, you have a bad/poor connection somplace in the signal path that it seems to be affecting all channels. I doubt it is induction from just being too close to another component, it sounds like it is too loud and also intermittent for that.

The problem is either in the receiver, or one of the cables plugging into the back of the receiver sucks and is grounding or something and causing staticon the ground buss perhaps.

Disconnect one cable at a time from the back, or just start wiggling them a bit if this occurs again and I'll bet you find the culprit.

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It woud be interesting to hear how this works out.

My guess is that the source of the noise is some appliance which turns itself on an off. This could include a furnace, air conditioner, fan, or refrigerator. That seem a bit more likely than a shielding problem alone.

One way hunting this sort of thing down is to use a battery powered AM radio. You could leave it in the listening area and turn it on when the noise invades the system. Then you can use it to hunt around the house. Notice the directional characteristics of the internal ferrite bar antenna. You may have to twist it around.

That is not to say there can't be a shielding or ground issue, too. Lack good shielding or gound could well be what is letting the noise into the system.

If is is an appliance you can force it to run to make the noise while you experiment with connections.

I note this is a new installation. If this was an old one, we'd have to consider what was the last change to the system.

Let us know.

Gil

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Thanks for all the responses!

I have not had much time to investigate lately. The problem seemed to go away when I moved the receiver away from the other components but after a couple days it was back (but fainter than before) and today after work it was back in full force. It was as loud as ever today while watching tv. The room is in the basement/lower level of our new house. The oil furnace is through a wall relatively close to the setup. I don't think it happens every time the furnace runs but am not positive (it provides out hot water so it runs year round). I have mostly high quality cables with the exception of the sat to rec cable which is a fairly high gauge no-name rca bundle (L,R,vid):

rec to speakers: monster wire w/ monst connectors

rec to TV: component

dvd to rec: component, dig coax

sat to rec: rca bundle (red, white, yellow)

Could this cable cause a prob? I have yet to hear it while watching a dvd but the wife says she has seen the problem during dvd operations. [We never turn the sat box off] Disconnecting this cable did not stop the buzzing noise.

Today when I was hearing the buzz again, I moved the speaker cable to the RH front channel and the noise stopped (coincidence or not, I do not know).

Also, I have the tv power cable plugged into the rec and the rest of the power cord run to an APC surge protector.

**I JUST REMEMBERED: I had to get one of those stupid Radio Shack remote wireless phone systems for the sat box which requires a phone jack. The sender/source is upstairs and the receiver is right next to the HT. What does it use? RF, I think. Maybe that is the problem?? I need to unplug it the next time we get the buzz in the HT.

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Would there be any way for you to record the sound for us? Due to the crazy inperiodic symptoms I am led to believe it is some other form of interference...do you think it could be your cell phone? Maybe I'll go record some samples of different kinds of interference and you can identify which one is closest - that is if you can't record it for us.

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  • 4 weeks later...

Sorry it has been a long time but things are hectic with a new house. Anyway, I am still seeing this problem.

I had a friend over the other day and it was making the noise and removed the manual for it which I had sitting on top (of the receiver) covering some of the vents and the noise tapered off after a moment. It is not 100% reliable, but fanning into the vents in the top seem to help most of the time. How can a brand new HK be overheating?!? Am I screwed?

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I don't think I understand but was the manual always on the reciever? If so that is a big REASON why. Heat rises and if you block the vents on top you are asking for it. Maybe instead of putting the manual on the reciever you should read that it states do not block the vents at all not even a little as the device was made with the vents in mind.

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